Method and apparatus for the application of materials



June 3, 1952 s. LETVlN ETAL 2,599,465,

METHOD AND APPARATUS FOR THE APPLICATION OF MATERIALS Filed Au ,8, 1946 4 SheetseSheet 1 June 3, 1952 s. LETVIN ETAL 2,599,465

METHOD AND APPARATUS FOR THE APPLICATION OF MATERIALS Filed Aug. 8, 1946 4 Sheets-Sheet 2 INVENTORS SEMI/EL ETV/N @150 EP/lAwv 5 June 3, 1952 s. LETVIN ETAL 2,599,465

METHOD AND APPARATUS FOR THE APPLICATION OF MATERIALS Filed Aug. 8, 1946 4 Sheets-Sheet 3 INVENTORS GEQEGE HA 5 ATTORN Y June 3, 1952 s. LETVIN ETAL' 2,599,455

METHOD AND APPARATUS FOR THE APPLICATION OF MATERIALS Filed Aug. 8, 1946 4 SheetsSheet 4 ATTORNEY intervals throughout its length in addition to being supplied at the ignition end. Fuel is conducted from the relief valve 2| to the nozzle 38 through line 39 having a control valve 40. The fuel introduced into the combustion chamber is ignited by a spark plug 4! to which current is supplied through wire 42 by a magneto 43, Figs. 2 and 10, coupled to the fuel pump [1, both of which are driven by a gear 44 which meshes with and is driven by gear 3|. The pressure of the air introduced into the combustion chamber is indicated by an air pressure gage 45 connected with the air duct 33.

Hot air mixed with the products of combustion of the fuel consumed in the combustion chamber, flowing from the combustion space of the chamber 34 passes through a duct '46 into an atomizer 41 to which insecticidal or other treating material is supplied through a pipe 48, Fig. 3.

tion of products of combustion is relatively small 7 and for convenience the hot gases passing into the atomizer may be referred to as hot air." If an air heater were used in which the combustion did not take place directly in the heating chamher then only pure air would be supplied. The presence of the products of combustion is however immaterial. Pipe 48 discharges the treating material or formulation into a-nozzle 50 having at its discharge end portion, aseries of discharge orifices 5| arranged radially to the nozzle axis, through which the material is discharged into the rear portion of a stationary atomizing cup 52 having a series of tangentially disposed air passages 53 at the rear portion of the cup through which hot air is introduced into the cup and is caused to whirl therein. The rotating hot air stream picks up-the insecticidal material and carries it to the outer end of the cup where the air' and material are discharged in a radial direction. "It will be noted that the open end of the cup 52 extends to or slightly beyond the front face of the atomizer so that the discharge of the material takes place directly into the atmosphere and not into aconfined spaceor chamber. As

the material in the cup has been brought to a the cup is heated by the portion of the hot air entering through the ports 53 and by the heated wall of the cup itself. Preferably the inner wall of the cup is tapered slightly towards the open end, as shown in-Fig. 3, although this is not essential. Hot air also fiows around the outer cylindrical surface of thecup 52 excepting for the rear-portion which is protected by a cylindrical shield 54, and the air passes out of the annular opening 55 in a direction substantially parallel to the axis of. the cup, where it strikes the thin film of formulation at approximately right angles, and shears the material into pminute particles. These particles can be varied from. about .5 micron in diameter to about microns and upwards depending upon the rate of flow of the formulation and the quantity, pressure and tem peratureof the hot air.

It will be observed that the introduction of the more or less heatedmixture of formulation and air or gas issuing from the mouth of the cup into 4 the main body of heated air or gas issuing from the heater 34 through the annular opening 55, which may for convenience be termed the main air blast, takes place in the open atmosphere just as the mixture and air blast issue from their respective orifices, or even slightly beyond the actual margins of the orifices, and not in any duct or confined space. There is thus immediate freedom for expansion of the gases and vapors in radial directions as well as longitudinally outward from the atomizer. This has an important effect in producing a fog of desired particle size which has great persistence and spreading and penetrating power. At the same time the body of fog is more or less confined and directed outwardly by what may be thought of as an envelope of heated air issuing from the orifice 55 and forms a column of fog, so to speak, which may be directionally controlled and projected to considerable distances. Of course the generally radial discharge of the mixture from the mouth of the cup 41 causes a thorough intermingling of the same with the wall of the tubular envelope of the main blast, but the latter being in much larger volume than the mixture issuing from the cup has suflicient directive force to project the column of fog to the desired distance and in the desired direction. a

The persistent quality and uniform character of the fog produced in the described manner is due, not only to the thorough breaking up and mixing of the formulation with the heated air, but also in part to the fact that the heated mixture of formulation with the relatively small body of the heated air in the cup is released into the larger partof the heated air or main blast in an entirely unconfined space, after both fluid streams have issued from their respective orifices.

The construction of atomizer described, and particularly the fact that in such construction the formulation mixture is discharged directly from the cup 52 into the atmosphere and main blast, causes the formulation material to be subjected to the relatively high temperatures obtaining in the cup for but a very short period of time. This is particularly important in the case of some formulation materials which would be injuriously affected if subjected to a more prolonged period of heating. Furthermore, the danger of carbonization in the cup and possible fouling of the apparatus is minimized.

As the fog produced by the atomizer above described issues directly as a stream or column into the open atmosphere the use of flexible hoses or the like for directing the stream is unnecessary as well as undesirable except under certain spe-'- cial conditions. In order that the stream may be orientated so as to project itself in the proper direction, it is desirable to mount the atomizer head on a universal mounting. In the construction shown a firm and simple mounting for the atomizer head is provided in which the latter is carried at the end of a short jointed duct which supports it directly from the heater 34 so that thisfjointed ductconstitutes both the support for the atomizer head and the means for permitting its universal adjustment. A preferred construction for this purpose is as follows:

The duct 45, Figs. 1, 2, 3 and 4, has three sections 56, 51 and 58 which are so interconnected that the section 58 which carries the atomizer is capable of universal movement so that the atomizer may discharge in any predetermined direction. Section 56 is fixed to the combustion chamber 34 at its inlet end and has its outlet end sea-ecaeee cured toa connecting section-'59 having a tapered end 60 which receives therein the inlet end of the section 51, the interfitting sections havin registering ball bearingraceways-whi-ch receive balls 6lintroduced through flller opening. 62 which'is closed by plug63. An annular-sealin ring 64. between the end of section 5.1 and the axially opposed portion-oisection 56=preventsthe escape of hot air from the concluitat the joint. With this arrangement, the inlet endofsection 57. may be turned.380 with respect-to theoutlet end of section BBabouttheir common. axis so that the outlet end of sectioniimay be moved to any desired position in its circle of rotation. Theoutlet end of section 51 has-an annular flange 65 which receives the inletendof. section 58, the interi'itting. parts also having ballibearing. raceways-whichreceive balls-66 introducedthrougha filler-openingclosed bya plug '61. Anannular sealing-ring ES-preventsleakage between the sections 51: and 58. Thus, sectionEE-may beturned through an angle of 360 with respecttothe outlet-end of section -l-about theircommon axis. Accordingly, with sections capable. of: rotation through arcs of 360 in directions at right angles to each other, the conduit d6 provides a mountingfor' theatomizer so that it can bepositioned to discharge the formulation fog in any direction.

Means alsoareprovided for locking section 5?- of conduit 46 in the desired position with respect'tosection 5B, and for similarly locking section 58' in any. predetermined position with respect to section 5'1. As shown, such locking means comprises a U-shaped latch, Figs. 3, 4 and 6, having legs 69, each of'which carries an extension 18 having at its outer end a tooth H which isshaped to fit the spaces between adjacent teethlz on the connecting section Etand the section 57. A coil spring 73 surrounds the intermediate portion of each extension in, the ends of which gear against a shoulderon the outer end portion of the extension and a guide 14, thus urgingthe latch; toward locking posit-ion. The enlarged outerend portion of each ex.- tension moves in aguide i5- and a sleeveh-i extends between the guides it and i5 and covers theextension and the spring. The latch has a handle ll-by which it is grasped to move it tounlockedposition against the action of springs 13. With this arrangement, when it is desired to change the direction in which the nozzle discharges the formulation fog on aerosol, the positionsofthe sectionsiii; and Stare-changed by moving the'latches to unlocked position, moving thesections to the desired positions andthen releasing the latches telocl; the sections in the new positions.

The insecticidal or other treating material is introduced into a container 13, Figs. '7, 8, 9- and 10, through an opening in the upper end which is closed by'a removable cover 19. The material is withdrawn'from the lowerportion of the con-. tainer TSthrough a pipette having an opening 8! in the wall of the lower end thereof, the discharge end ofthe pipe 80 being connected toa fluid pump 82, Figs. 2 and 10, which is mounted on'fue'l tank [2 and is driven by gear-44. Pump 82 discharges the formulation into pipe 83 and into pipe 48 through which it is conducted to the atomizer ll. In passing through pipe. 28 the material flows through a metering valve 8 1 and a control valve 85. A pressure gage 86 connected by pipe 81'- to pipe- 83' indicates the pres sure of the material flowing tothe atomizer. The.

pressure of. this .flowingtmaterialtis. (:0Z1t11011Qdb-. a pressure control: valve. 88 .in..a pipe 189,. the.-.i'n.-'-. letaend ofwhich.connectswithsupply .pipe 835 throng-ha. branch pipe :38, .andthe outlet; end. of which connects. with .the ..upper end. of .a return.

pipe-9 Lw-hich is disposedtconeentrically to, ;out-. sideof: and in spacedv relationship totthe .inlet end. oflp'ipefiil, as 'shownin-Fig. 7; .A. safetyivalve. 92 is.connected2.to the juncture of pipes 89,.and 9ethrough pipe. 9.3., and: to .the. outlet. endtpore. tion. of pipe 89 throughpipeQt. Pipe. 91: hassan. outlet opening 95 near its lower end which .is. disposedsorthat thematerial returned to. .the.con-

tainen. is. discharged. .2. direction.substantially.

tangent .to the. wall of the. containentherebysetting the. fluid. in. the container-in rotationand;

resulting in continuous agitation. otithe ,insectie cidal material. To maintain. the discharge .opening. fifilinits. proper tangent position, the. upper end: portion of the return pipe:9:l has two. pins.

9%, Fig.3, fixed to the outenwalhof.-the-. pipe;in

diametrically opposed relationship, andthesepins. are received in. slotsiili in-a boss/'98. on; theupper...

portionof the. container. :Withtheproper initial relationship between the discharge. opening .95;

and the pins 96 and slots 9'5, thedischargeopeming will bein the. tangential. discharge positicn as:long as thepins. at. are. in.the slotsifil.

In operation, theinternalcombustion. engine. 26, is started, whichdrivesthe -.b1ower. 32, -the. fuel. pump I l, the magneto-A3.andtheinsecticidalmaterial pump :82. The blower 6111)}.31185 13111'. v:to

the combustion chamber 34, .andthe pump ,IJ. supplies fuel thereto. In: the combustion. cham-' her-the. air is heated to. approximatelyz900sE and isconducted.tetheatomizentl under a1pressureof: approximately 35ps. i.

caused torotatein a thinsfilm inthecup 752 and tostrikethe main blast or surrounding envelope of hot air.at approximately right. angles upon-its discharge from the. cup. with the result that. the

material is sheared into minute particles of con.-

trolled size. The sections of the conduit .45.. are adjusted so that the insecticidal materialzwillibe delivered; inv the desired. directionand to the specified: area. The airpressurev in the combustion. chamber isvaried by changing. the speed. of: the,

blower 32 which is. eiiected: by varying the .ispeed. .of the enginezfi.

from. about .5 to 60. microns, or. from fogscreen size to and including that obtainable by ordi-.

nary-sprayers. The mass of theparticlesis such that the air currents carrythem .for relatively. long distances-and thus effect a uniform deposition of the insecticidal fluid over largeareas. Ex-

perimental results. have shown that these fine particles will not onlycome torest on the top. of plane surfaces, butdue to eddy currentswhich are inherent in thick. vegetation, will be de-. posited on the under sides of objectsand into the tiniest crevices.

The formulation is delivered at alowpressure to the atomizercup 52 and the quantity-so. de-

livered is regulated by manipulation of the con-..

trol. valve thindependentlymf the speed ofpump 82-, the. capacity of: which is. greater. than the} Pump-82 supplies. insecticidal material to. the atomizer where itrlst maximum quantity of material required for the atomizer. Valve 85 is a quick opening and shut off valve. The excess material delivered by pump 82 is returned to container 18 through lines 9|] and 89, or through lines 90, 93 and 94, depending upon the setting of the pressure control valve 88. The returned material is discharged tangentially to the tank wall, so that a continuous rotary motion of the insecticidal material is maintained in the container, thereby keeping suspension and suspensoids in a state of homogeneity.

In the form of the invention selected for illustration, the same fuel is utilized for the internal combustion engine 26 and the combustion chamber 34, but it will be understood that different fuels may be used.

With this machine, a very even deposit of minuteparticles is obtained at remote distances from the machine, thus providing an economical arrangement, both from the use of a minimum of insecticidal material and labor of application. The machine is compact, comparatively light in weight, and deposits the formulation more evenly, more widely and more rapidly than is possible by spray machines.

As used in the claims, the expression insecticidal material includes within its scope insecticides, fungicides, repellents and hormones, as well as other materials for accomplishing a similar or other purpose. As described above the heated gas delivered from the combustion chamber is largely air, such products of combustion as are present having no specific effect. The amount of products of combustion present depends simply upon the amount of fuel used for producing the heated blast. If the air is heated by an external source there would be no products of combustion, or a blast may be used containing any mixture of air and other gases. In the claims the blast is referred to as hot air which is intended to cover air alone or any mixture which may be employed of .air and other inert gases or of such gases without air.

Inasmuch as the forms of the invention selectedfor illustration and description are preferred forms and are not intended to disclose the full extent of the invention, it will be understood that the invention is not to be limited excepting by the scope of the appended claims.

What is claimed is:

l. The method of producing an aerosol of treatment material in the open atmosphere, comprising mixing the material in liquid form with a relatively small amount of heated air, causing a large amount of heated air to issue under pressure from an orifice into the open atmosphere, introducing the heated mixture in fog forming proportions and under conditions producing minute subdivision of the treatment material into the air blast at the instant of its issuance from the orifice into the atmosphere and directing the resulting fog towards the area to be treated.

2. The method of producing an aerosol in the open atmosphere for application in the form of a fog to an area to be treated comprising producing a blast of heated air, splitting the blast into major and minor portions, discharging the major portion into the atmosphere, causing the minor portion of the blast to entrain a treatment formulation and combining the minor portion of the blast carrying the treatment formulation with the major portion of the blast under conditions producing minute subdivision of the treatment formulationsimultaneously with the discharge of the major portion of the blast into the open atmosphere.

3. The method of producing an aerosol of a treatment formulation in the open atmosphere for application in the form of a fog to an area to be treated which comprises discharging a blast of heated air into the atmosphere in the form of a tubular jet, causing a stream of formulation material to whirl rapidly about an axis concentric with the axis of the jet and discharging said formulation material into the center of said jet as the jet is discharged into the atmosphere whereby the whirling formulation material will be thrown outwardlyinto the tubular jet by centrifugal force and will form a fog therewith on issuance into the atmosphere.

4. Apparatus for producing an aerosol of insecticidal material comprising a heater, means for supplying air under pressure to the heater, anatomizer having a stationary cylindrical cup having an outlet end discharging into the open atmosphere, means for delivering insecticidal material into the cup, means for introducing heated air from the heater into the cup in such manner that it whirls therein and entrains the material and the whirling mixture is discharged from the outlet end of the cup in an outwardly deflected direction, due to centrifugal action, and means for conducting heated air from the heater to the area surrounding said atomizer cup and discharging it into the atmosphere around the outlet end of the cup invthe form of a substantially continuous annular blast substantially parallel with the axis of the cup into contact with the whirling mixture of material and air to form an aerosol of said material.

5. Apparatus for producing an aerosol of a treating formulation for dispersion in the open atmosphere comprising a heater, means for supplying air under pressure to the heater, an atomizer having concentric discharge outlets discharging into the open atmosphere, means for delivering the treating formulation to the atomizer, means for introducing heated air from the heater into the atomizer in such manner that it whirls in the atomizer and entrains the formulation material therein and the mixture is discharged from the inner outlet of the atomizer while still whirling and means for discharging heated air from the heater into the atmosphere through the outer concentric outlet of the atomizer in a tubular jet surrounding and in contact with said whirling mixture to form an aerosol of said formulation material as it is discharged into the atmosphere, the axis of the tubular air jet being substantially coincident with the axis of whirl of said mixture, the direction of discharge of the tubular jet being substantially parallel with said axis of whirl.

6. An atomizer for producing an aerosol comprising a casing having inlet and outlet openings, a stationary substantially cylindrical member in the casing having one end closed and its other and discharge end projecting through said outlet opening out of contact with the wall thereof so as to provide an annular, substantially continuous outlet space from the chamber around said discharge end, means for introducing material to be atomized into said member adjacent said one end, the cylindrical member having a passage through the wall thereof ad;- jacent said one end, means for supplying air under pressure through the inlet opening of said :material therein, the construction and-arrange .mentbeing such that the rotating material in said member is discharged from thedischarge 'end thereof in outwardly deflected directions :into contact with the blast of .air flowing from said annular outlet space.

7. An atomizer comprising a casing having an inlet and an outlet opening, a stationaryisubstantially cylindrical :member 7 in the casing having one end closed and the other end open and projecting into said outlet opening, and a tubular member projecting into the cylindrical member and having a closed outer end and an aperture in the side wall thereof through which material to be atomized is discharged radially into the cylindrical member adjacent the closed end thereof, the cylindrical member having an aperture in the wall thereof adjacent its closed end and disposed to discharge approximately tangentially to the inner wall of the cylindrical member, the construction being such that the material to be atomized is delivered into the cylindrical member at its closed end portion and is entrained in air delivered through the aperture in the wall thereof and is caused to whirl in said member and be discharged while whirling from the open end and into contact with a tubular air jet discharged from the outlet opening of said casing.

8. An atomizer head comprising a casing hav ing an inlet opening at one side thereof, said casing having a large circular outlet orifice in the front thereof, a cup mounted on the back of the casing, a duct for the material to be atomized entering said cup through the bottom thereof and having a discharge opening for discharging the material to be atomized near the bottom of the cup, said cup having an opening extending through the side Wall thereof in a substantially tangential direction for admitting air from the exterior to the interior of the cup, the open mouth of the cup extending through the orifice in the front of the atomizer head but out of contact with the walls of said orifice so as to provide an annular discharge opening from the casing concentric with the open mouth of the cup.

9. An atomizer head comprising a casing having an inlet duct at one side thereof, and having a large outlet orifice at the front thereof, a cup mounted on the back of the casing and extending transversely across the casing with its open mouth projecting through the orifice at the front of the casing but out of contact with the walls thereof so as to provide an annular outlet opening from the interior of the casing concentric with the mouth of the cup, a duct for material to be atomized entering the cup through the bottom thereof and projecting part way into the cup and having a closed outer end, said duct having a plurality of radial discharge openings in the side wall thereof, the cup having a plurality of tangential openings through the wall thereof in a region adjacent to the radial openings in the duct.

10. An atomizer comprising a casing having inlet and outlet openings, a stationary, substantially cylindrical member in the casing having :10 a discharge and projecting through said -.out'- let opening out of contact with the wall thereof so asztoprovidean.:annular, substantially continuous outlet :spacefrom the casing around said discharge end and parallel with the axis of said cylindricalmember, said cylindrical memberhavinga plurality of spaced passages through the cylindrical wall thereof with their discharge ends substantially tangent to the inner wall surface and discharging in a substantially circumferential direction into saidmember for admittinjg "a gaseous medium under ,pressureftogpass "from the easing into, said-cylindrical enrember andto flowaround the interior of said":mem-

tber an'dout of the discharge-end thereof,i and means for introducing a liguidrto be 'atomized :intosaid"cylindrical .memberwin a direction to impinge upon the inner cylindrical wall-thereof,

the construction and arrangement being such that upon the introduction of a gaseous medium under pressure into said casing, some of the gases will pass into the cylindrical member through said substantially tangential passages and will rotate in the member, and cause the liquid delivered thereinto to rotate in a thin film to wards the discharge end of said cylindrical memher where, due to centrifugal action, it will be discharged in outwardly deflected directions into contact with a blast of the gaseous medium issuing from the casing through said annular outlet space.

11. Apparatus for producing an aerosol of insecticidal material comprising an atomizer, a container for the material, a pump for delivering material from the container to the atomizer, the pump having a capacity larger than required to supply the material to the atomizer, means for returning the excess material to the container in such manner as to cause the material in the container to move continuously in rotary motion, means for controlling the quan-- tity of material supplied to the atomizer from the container, a combustion chamber, a fuel reservoir, a pump for supplying fuel to the combustion chamber, valve means for controlling the quantity of fuel supplied to the combustion chamber, a blower for delivering air to the combustion chamber, an internal combustion engine for operating said pumps and blower, an igniter for igniting the fuel in the combustion chamber to heat the air supplied thereto by the blower, and a conduit connecting the combustion chamher and the atomizer, the conduit being constructed and arranged for universal movement of the atomizer so that the atomized material may be discharged therefrom in any desired direction.

12. Apparatus for producing an aerosol of insecticidal material comprising a base, an internal combustion engine on the base, a blower on the base actuated by the engine, a combustion cham-- bar on the base, a fuel burner for the chamber, a pump on the base actuated by the engine for delivering fuel to the burner, a conduit connecting the blower and the chamber through which air is delivered to the chamber and is heated therein, an atomizer, a pump on the base actuat ed by the engine for delivering insecticidal material to the atomizer, and a conduit connecting the chamber and the atomizer through which heated air is delivered'to the atomizer for contact with the material to form an aerosol of the material, the last mentioned conduit supporting the atomizer and having connected sections which are movable with respect to each other.

SAMUEL LETVIN. GEORGE P. HAYNES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 993,365 Barker May 30, 1911 1,023,707 Anthony Apr. 16, 1912 1,339,579 Bunyan May 11, 1920 1,474,603' Morse Nov. 20, 1923 1,567,482 Anthony Dec. 29, 1925 1,723,955 Shepherd et a1 Aug. 6, 1929 1,946,696 Johnson Feb. 13, 1934 Number,

Number Name Date Parker Sept. 3, 1935 Collins July 28, 1936 Batt Feb. 9, 1937 Emery Apr. 26, 1938 Witham, Jr. Dec. 6, 1938 Kosik Mar. 12, 1940 Erickson May 28, 1940 Wadsworth May 27, 1947 Levey et a1 June 10,1947 Shade Oct. 21, 1947 Besler Dec. 9, 1947 Langmuir et a1. Mar. 16, 1948 FOREIGN PATENTS Country Date Great Britain Feb. 10, 1928 

